Electric switch.



UNITED STATES PATENT OFFICE.

WILLIAM C. STEVENS, OF SUMMIT, NEW JERSEY, ASSIGNOR TO THE GUTLER-HAMMERMFG. CO., 0F MILWAUKEE, WISCONSIN, A CORPORATION OF WISCONSIN.

ELECTRIC SWITCH.

Specification of Letters Patent.

Patented June .18. 191 R.

Application tiledA April 4, 1916. Serial No. 88,864.

To all 'whom it may concern:

Be it known that I, VVILLrAM a citizen of the United States, residin atSummit, in the county of Union and tate of New Jersey, have invented newand useful Improvements in Electric Switches, of which the following isa full, clear, concise, and exact description, reference being had tothe accompanying drawing, forming a part of this specification.

This inventwn relates to improvements in electromagnetic switches formotor control and other purposes and more particularly to that type ofswitch wherein a single e011 serres to actuate the same and also torestrain its operation during excessive current conditions.

The invention has'among its objects to provide a :switchv of theaforesaid,type which will be more positive and reliable in operation andsusceptible of a wider range of adjustment than those heretoforeproposed.

A further object is to provide such a switch wherein adjustment may beobtained without atlecting the magnetic circuits thereof.

Other objects and advantagesof the invention will hereinafter appear.

The invention will now be more speciically described in connection withthe accompanying drawing which illustrates one of the variousI possibleembodiments thereof.

In the drawing,

Figure 1 is a front elevation of the switch, and,

Fig. 2 is a, side elevation thereof partly in section.

The switch includes cooperating contacts 1 and 2, the former heiligfixed to a support 3 upon a panel ft and the latter heilig yieldinglymounted 'in a conventional manner upon a movable arm 5. The arm 5 islnounted upon a pivot pin (i carried by a'ud bctween extensions 7 ofnou-magnetic bracketS fixed lo the panel 4. The' arm 5 is hifurcated orlongitudinally slotted, to slraddle the hracket B and receive a .secondarm 9 also pivotally mounted upon the pin 6. These two arms formarmatures for an electromagnetic winding l0, and said arms arc sodesigned that the mechanical inertia of the C. STEVENS,

, former will materially exceed that of the mounted on panel 4. The core11 is ositioned to aline with the upper end o the arm 9 while plate 12has an extension 13 paralleling the core to aline with the upper end ofarm 5. The core 11 and extension 13 thus form holes for the arms 9 and 5respectively and said arms are respectively provided with non-magneticplates 11 and 15 to prevent sticking thereof to said poles` Both arms 5and 9 have rearward extensions, the former having a slotted extension5." and the latter an extension 9 fitting Within the former. Extension 5carries a cross bar 17 forming a stop for extension 9 and sab.y crossbar has an adjustable stop screw'lS to engage bracket 8, said extension5 being bifurcated to straddle said screw. The arm 9, including itsextension, is of magnetic material but the arm is of magnetic materialonly from its upper extremity including the entire extension 5, being ofnon-magnetic material. However, thenonmagnetic extension 5 is providedat its rear end with a magnetic block 19 in line with the end ofmagnetic plate 12 which projects downwardly through bracket 8. Thefront.

face of this block is in close proximity to the' magnetic flux thereofwill hc divided between the two paths indicated in broken and dottedlines. The flux taking the broken line path obviously tends to attractthc arm 5 to close the switch, while that taking the dotted line pathtends to attract the arm 9. Further, it will be observed that the fluxtaking the dotted line p'ath, in passing'through the magnetic block l!)attached to `the extension of arm 5 :in its way to the extension of armS), also sei-vesto attract or holdA said block with the result ofopposing,lr thx-attraction o1' arm 5 bythe flux taking the broken linepath. Moreover, in view of the relation of the block 19 and extension 9ol' armi), said arm may move to attracted position without varying theattractive force exerted on the block 19 and hence the force inopposition to the closure of arm 5.

The arm 9, however, is connected tothe 75 I to the point X, theremainder of said arm. i f

inertia of said extension of arm 5 through a tension spring 20. rl`hisspring is connected at one end to a lug 21 on the magnetic block 18 and1s connected at its opposite end by an adjustable device to a lug 23 onthe extension of arm t). Hence it will be observed that when tli i arin9 is attracted it will tension the spi-ing 20 thereby offsetting orcompensating for the mechanical inertia of the ariii 5 to the extent ofthc energy stored in said spring. In other words, the arm 9 uponattraction increases the sensitiveness of the ai'iii 5 to attraction bythe magnet through the iiiediuin of springr 20.

Thus, considering the switch iii its entirety, the winding 1() whenenergized will exert opposing pulls on arm 5 and a unidirectional pullon arm 9. The pull on arm 9 is opposed only by the relatively slightmechanical inertia thereof and the minimized opposing force of spring20,. while the magnetic opposing pull on arm 5 1s supplemented by therelatively great mechanical arm. Arm 9 will accordingly respond prior toarm 5 and in approaching pole 1l reduces the reluctance of the path ofthat flux actingr to attract the same and to oppose attraction of ai'm5. This insures a strong opposingr same time eti'ects a change in therelative relnctances of the two magnetic circuits whereby a decrease incurrent will effect a greater reduction in thc flux of the dotted linecircuit than in the linx of the broken line circuit. Moreover, theattraction of arm 9 tensions the spring 21| to supplement the closingpiill exerted on arni 5 whereby at sonie critical currentl value thecoinblned magnetic and mechanical forces exerted on arm 5 willnecessarily preponderate the combined magnetic and mechanical opposingforces to close the switch. On the other hand, the constructiondescribed insures a time elenieiit in the closure of the switch wherebyit' the winding is initially subjected to a current rising above saidcritical value the pi'epoiideration of the two opposing forces willnecessarily be reversed with the resultof maintaining` the switch inopen position until the current falls to said critiral value.

lf desired. the arni 5 may be designed to have, such ii'iechaiiicalinertia as to posi tively insure against its attraction without theassistance of spring 20 oi' any of the well known means may he providedto retard the building up of the linx of the broken line circuit uponinitial energization of winding 10. Such means will positively insure anopportunitV vfor action of thc. other means to control the switch asdescribed. ltloieover. with the construction described, thesensitivcness of the ariii 5 for attraction by winding It), and hencethe critical current "aluc, may be varied through a wide range pull onarin 5 but at the' of such pulls by mechanical and magnetic adjustments.The mechanical adjustment is afforded by the adjustable device 22associated with the tension spring, which device enables varia,- tion ofthe degree of tension of spring 20 effected by attraction of arm 9.Thisnin turn, varies the degree of supplementation of the closing pullof magnet 10 and without in any wisc affecting the normal positioningof,the arm 5 or, in other words, without in any wise affecting eitherinagnetic circiiit. 0n the other hand, the magnetic adjustment isprovided for by the adjustable stop screw 18 on the extension of arm 5,which provides for variation of the air gap between the lowerextremityof the magnet frame and the magnetic block 19 on arm 5, andproportional variation in the air gap between the arm 5 and pole'13..This in turn effects a variation in the relative reluctances of the twomagnetic circuits with a consequent variation in the effect of risingand falling currents upon the fluxes of the two circuits. Obviously,therefore, these adjustments individually vide for adaptation of 'thevarying conditions.

It will, of course, be understood that when the switch closes the arm 5ap roaches poles 13 and 1l of the magnet to re uce the reluctance of thebroken line magnetic circuit and at the same time separates the block 19from the loweiend of the magnetic frame to increase the air gap in thedotted line magnetic circuit which insures a strong holding pull on arm5 and further insures against subsequent prcdoinination of the opposingfluxes. j

WVhat I claim as new and desire to secure by Letters Patent is:

In an electromagnetic switch, in combination, coperating switchcontacts, an actuating member for one of said contacts, electroinagneticmeans subjecting said member to opposing pulls variable relatively byvariations in the current supplied to said means and means adjustable tovary the sensitiveness of response of said member for aotua tion of saidcontact whilemaintainin a given relative adjustment of the opposingpulls of the said electromagnetic means.

In an electromagnetic switch, in combination, cooperating switchcontacts, an actuating member for one of said contacts, electromagneticmeans subjecting said meinbei-'to opposing pulls variable relativeljr bv variations in the current supplied to said means, means to eti'ectrelative adjustment for response of said member at any one of a numberof critical current values and means adjustable to vary thesensitiveness of response of said member while maintaining a givenrelat-iveadjustment of the opposing pulls of said electromagnetic means.

and jointly roswitch to wi ely 3. In an electromagnetic switch, incombination, coperating contacts, an actuating.

member for one of said contacts, an electromagnetic operating windingfor said member having magnetic circuits whereby its magnetic fluxexerts opposing pulls on said member and means subjected to auni-directional pull. by said Winding and responsive to vary thesensitiveness of response of said member.

4. In an electromagnetic Switch, in combination, cooperating contacts,an actuating member for one of said contacts, an electromagneticoperating winding for said member having magnetic circuits whereby itsmagnetic linx exerts opposing pulls on said member and means subjectedto a uni-directional pull by said winding and rcsponsive prior to saidmember to supplement the magnetic pull on said member in a singledirection.

5. In an electromagnetic switch, in combination, coperating contacts, anactuating member for one of said contacts, an electromagnetic operatingwinding for said member having magnetic circuits whereby its magneticflux exerts opposing pulls on said member-and means subjected to auni-directional pull by said winding and responsive prior to said memberto mechanically supplement the magnetic pull on said member in a singledirection.

6. In an electromagnetic switch, in combingtion, copcrating contacts, anactuating member for one of said contacts, an electromagnetic operatingwinding for said membei' having lmagnetic circuits whereby its magneticlinx exerts opposing pulls` on said member and means subjected to auni-directional pull by said winding and responsive prior to said memberto supplement. the magnetic pull on said member in a single direction,said means being adjustable to vary the degree of supplementation of thepull on said member.

7. In an electromagnetic switch, in combination, cooperating contacts,an actuating member for one of said contacts, an operating winding forsaid member having magnetic circuits whereby its magnetic linx cxertsopposing pulls on said member and means responsive to said windingindependently of said member to vary the reluctance of the magneticcircuit, thc flux of which opposes actuation ot said member.

8. In an electromagnetic switch, in conibination, coperating routards,an actuating member for one ot said contacts, an operating winding forsaid member having magnetic circuits whereby its magnetic flux ex ertsopposing pulls on said I nember and means responsive to .said windingindepend ently of said member to vary the reluctance of the magneticcircuit, the flux of which opposes actuation of said member, said meansupon attraction also acting to supplement the reverse pull on saidmember.

t). In an electromagnetic switch, in combination, cooperating contacts,an actuating member for one of said contacts, an operim 10. In anelectromagnetic switch, in com- 30 bination, coperating contacts, anactuating member for one of said contacts, an operting winding for saidmember having magnetic circuits whereby its magnetic flux exertsopposing member having means to adjust the Same for relative reluctancevariation 4of said magnetic circuits, and means subjected to auni-directional pull by said winding and.

responsive thereto to supplement the actut 9 atin pull on said member,said means 1ncluding adjustable means for varying the degree of suchsupplementation.

11. In an electromagnetic switch, in combination, cooperating contacts,an actuating member for one `of said contacts, an operating,r windingfor said member having magnetic circuits whereby its magnetic fluxexerts opposing pulls on said member, said member having means foradjustin same to vary relatively the norma reluctances of said magneticcircuits, means subjected to a uni-directional pull by said winding andadapted upon response to reduce the reluctance of one of said macircuits and means controlled bysai former means to supplement theactuating pull on said member, said last mentioned means bein adjustableto vary the degree of such supp ementation. i

12. In an electromagietic switch,in.eoml bination, cooperating contacts,an electromagnetic wjnding and separately and progressively respondingamature members for said winding, the member last to re 115 spend beingoperatively connected to one of said contacts for actuation thereof andsaid windingr having a magnetic circuit including both ot said members,such circuit subjecting said contact actuating member to a 12orestraining pull and being subjected to a reduction of its reluctanceupon response of the other of said members.

I3. In an electromagnetic switch, in com- 9.'7 said magnetic" to auni-directional pull: f;

pulls on said member, said 35 the 10a etic los bination, coperatingcontacts, an electro- 1,25`

magnet having separately and progressively responding armature members,the member last to respond heilig operatively connected to one of saidcontacts for actuation thereof, said electron'iagnet having a magnetic13oy circuit including both of said members, such actuating pull of saidcontact actuating circuit subjectlng said contact actuating memberfollowing the attraction of the member to a restraining pull andbeing-subother of said members. 10 jected to a reduction in itsreluctance upon In Witness whereof, I have hereunto subs response of theother of said members and scribed my name.

an energy storing connection between said armature members acting tosupplement the WM. C. STEVENS.

